Safety crank for engines



July 6,1926. 1,591,103.

R. G. ROBERTSON SAFETY CRANK FOR ENGINES FiledMarch 23, 1925 Hubert 5.1 16212? 5cm.

t Patented July p I TiES " nonnn'r e.-no13nn*r'son, or CUMBERLAND oI'rY, 'rnnnn'ssnn.

SAFETY onANK FORENGINEgfJ-if v I Application filed- March 23,1925. .s r ia1]no.. 17,74m

This invention relates to improvements insafety cranking apparatuslforguse in connection with internal combustion engines.

The pr mary ob ect; of this. invention is the PIOVlSlOIl of'ja safety crank ng mechanism for internal combustion; engines, em; bodylng a novel release'clutching mecha; nism which will permlt the conventional use of rtheha nd crank, butiwhich will release the hand crank from the crank shaft of the.

internal combustion engineupon backfire in the latter. v

A furtherobject 'of this invention is the provision of a novel type of hand crank mechanism for use 1n ,COIlIlGCtlOIIWlth inter-l ventioniwill be apparent during the course ofthe following detailed description.

In the accompanying drawing, forming a part of this specification, and wherein similar' reference characters designate corres-g ponding parts throughout the several views,

Figural is a side :elevation of, the improved safety cranking device, showing the 7 application of the same upon an internal combustion engine, for cooperative use in connection with cranking thereof. I

Figure 2 shows thegimproved. this inventlon in a frlctlon'clutchln'g pos1-.

tion similar tothat when a cranking pera-f tion is being effected.

F gure 3 1s across sectional st'antially on'the line 3, 3of Figure 1.

Figure is across sectional View, taken through the improved device substantlally 3 v V on the line l-Aof Figure' l, 1

of illustration is shown nly a preferred embodiment of this invention, the-letter A may generally designate an-. internal cOmbustionf eng ne, vupon Y which the mprovedj safetycrank deviceB isusedl The internal combustion engine A maybe of any approved character, Comp ising the engine casing and crank shaft. 11.; ,On'

the end of thecrank sha ftf1l the conveng tional hand'cr'ank engaging cap or member 12. is provided which has apin 13 therein; which the catch member of thesafety crank B adapted to engage to effeot a cranking operation.

mechanism Oth r objects and advantages of this in-.

details 0 view. takenf through the details of this invention sub-- ii The safety cranl;TB preferably comprises i Q the crank body; 20, having a shaft portion 21 gournalled'in a bearing 22 of theinternal combustionengine casing 10, so that-said shaft p'ortion' 21 is reciprocable in the bearternal combustion engine. shaft 1 11. v

The' shaft p'o'rtionzQl at its end adjacent" thecrank shaft lloftheinternal combustion engine is. preferably provided :with' a" in'g,and is in axial alignment with the i115;-

tiidinally of said shaft. Thiscatchmember 25 comprises a hollow cylindrical shell provided; with teeth 26 (adapted. to receive thepin13 therebetween for'the purpose of connecting the crank shaft with the hand crank. .This catch, member 2-5, includes a sleeve portion .27 rotatably journalled on the, hand crankshaft vportion 21, and the sleeve portion '27; is, of course reduced with 'respect tothe catch member 25.. At the end of the sleeve '27, in' spaced relationfrom'the wall 28 of the catch member is. a disc ,30, keyed as at-S l to said sleeve, and providing a space- 32' between the said} disc and the wall '28 for rotatably supporting a ratchet.

wheel clutch member 34, whichiis not only rotatable on said sleeve'portion 27,;but-is' reclprocable between thev disc and-thewall'28, 7-"

:Fixedupon the crankshaftlportion Q1, is"

a collar 38, keyed -asat 39, which maybe of substantially the same-diameteras the disc 30. This collar 38. is disposed-on the shaft portion 21 at the opposite side of'the disc 30 from the ratchetwheel 34,,andit is connected withthe ratchetwheel 34- by means ofpivot-g ed connecting bars or; links 4:0, said bars being provided; tWo in number, and pivoted,

asat 411st diametrically opposed pointson". In the drawing,wherein for the-purpose the periphery of the collar -38,and extending isfof course of greater diameter; than either across the periphery of the disc 30,..and thru suitable jarcu'ate" openings 45, in the loo 'r-atchet'wheel-- 34. The ratchetl-wheeli3k thejdisc 01 the collar '38. At their ends at the opposite side of theratchet wheelyBL from the disc 30, therconnecting links40 are I pivotally connectedwith cleats 416,- as by means of pivot pins 47; .said cleats 46-beingrigidly. connectedfwith the ratchet 71168134,

ratchet wheel 34 from the;-.disc;.30;;

1 Th 'ratcl1et-, heel 34f is',' provided with I t th '50 the; periphery thereof, i against, f

- serves as a fulcrum for the connectingv bars which a pawl '51 is adapted to be operated; said pawl 51 being a spring urged pawl carried by engine casing 10, to prevent rotation of the pawl of the ratchet wheel in one direction. f

Referring to the operation of the invention the safety hand crank device B is carried on the casing of the internal combustion engine normally in the position illustrated in Figure 1 of the drawing. A compression springBO at one end engages the bearing 22 and at the other end engages a pin 61carried by the hand crank 20, to urge the catch I member25 out ofengagement with the internal combustion engine crank shaft. To crank the engine it. is merely necessary to press'inwardly on the hand crank safety deviceB,which' willpress-the teeth 26 of the catch member 25 into engagement with the pin extension 13 of the crank shaft 11, as can readily be understood. .Upon'turning of the crank in a clock-wise direction, the collar 38 will of course be turned therewith,

and such movement will cause the connecting links 40 to pull the ratchet wheel 3 against the disc 30, and it will likewise cause the disc 30 to'be clamped in a friction clutching engagement between the collar 38' and the ratchet wheel 34:, to eflectively couple the clutch member in a connected engagement with the hand crank shaft 21, so that the engine crank shaft may be rotated. The clutcliing arrangement formed by the collar 38 and-the ratchet wheel clutch part 34 upon the disc is very firm, and the greater the effort required to rotate the crank shaft, the more firm will be the clutching engagement "of these parts" upon the disc 30, so that the catch member 25 will be keyed against sliding movement upon the hand crank shaft 21. Assuming that a backfire-takes place in the internal combustion engine, this will cause a reverserotation of the crank shaft 11. ,As the catch member" 251s connected with the internal combustion engine crank shaft, during such reverse rotation the catch member willmove with the crank shaft, and

at the start of therotation of the crankshaft the ratchet wheelfilwill tend to rotate therewith. However, due to the provision of the pawl 51, the ratchet wheel will be prevented from reverse turning, as is illustrated in Figure i of the drawings, and will be held stationary. As the connecting links i0 are passed thru the slots or openings in the "ratchet Wheel, said ratchet wheel thus d0. Upon further reverse rotation of'the crank shaft, the connecting links 4E0 will then tend to be straightened," to the position illustrated in'Figure l, which will push the hand crank shaft 21"outwardly, releasing the collar 38 from'its frictional clutching engagement with the disc 30, and'alsoreleasing the ratchet wheel'34c from its clutching en' gagement with the disc 30. This then positions the catch member 25 in a loosely coupled relation upon the hand crank shaft portion 21, so that the back-fire does not further move the safety hand crank device'B, and will thereby prevent injury to the operator. If desired, a pin 62 may be provided on the hand crank shaft 21 to prevent detachment of the catch member 25, but this pin is not considered essential, for the reason that the catch member 25 is held in'position on the shaft portion 21'by. reason o f-the disc 30,

From the foregoing description of this 1. In a safety hand cranking device for internal combustion engines a shaft,1a'catc'h member rotatable on said shaft including a disc portion, a clutch part keyed to said shaft at one side of said disc portion, a second clutch part rotatable with respect to-rthe shaftat the opposite side of saiddisc portion, and means connecting said clutch parts for gripping the disc therebetween upon rotation of the hand crank shaftwhereby to key the catch member toithe hand crank shaft. 1

. 2. In combination with an internal com bustion engine including a casing and a crank shaft, a hand crank shaftya catch member rotatably carried by the hand crank and adapted for connect-ion to said engine crank shaft, a disc keyed with said catch member, a clutch part keyed with said hand crank shaft at one side of said disc, a ratchet wheel rotatable with said hand crank shaft at the opposite side of said disc, means connecting the first clutch part with said ratchet Wheel whereby the same will frictionally clutch upon the disc to "connect the catch member with the hand crank shaft upon rotation of the same, and a pawl carried by said engine casing forcooperation against said ratchet wheel toprevent rotation of the same in one direction. 7

3. In adevice of the class described the combination with an internal combustion en gine including acrank shaft, a hand crank including a shaft portion, a catch member rotatable on the hand crank shaft portion for connection with said internal'combustion engine crank shaft, a disc connected with said catch member, clutch parts disposed at opposite sides of saiddisc one of which iskeyed to the hand crankshaft and the other rotatable 'with' respect to said shaft, link means connecting the said clutch parts together wherebytheyinay be moved into and out of frictional clutching engagement with the disc therebetween, and means for pre 7 venting rotation of the clutch part which is rotatable on the shaft of the hand crank ina direction counter to the cranking rotai tion of the-hand crank.

' the clutchpart whereby the collarand clutch" shaft,a discv keyed on said sleeve in spaced} relation with thefcatch member, a collar.

4. In a safety hand crank. for internal combustion engines a hand crank including;

a shaft, a catch member including'a sleeve d rotatablybearing on said shaft, a disc keyed on said sleeve in spaced'relation with the catch portion, a collar keyed on said shaft at one side of said disc opposite to the catch portion, a clutch part rotatable on's aid sleeve between the disc'and catch member, links pivotally connecting the collar with part may be heldinto andout of frictional clu 5. In a safety hand crank for internalcombustion engines a hand crank including a shaft,a catch member including a sleeve. rotatably bearlng on said shaft, a dlsc keyed on said sleeve in spaced relationwith the catch portion, a collar keyed onsaid shaft at one: side of said disc opposite'to the'catch "portion, a clutch, part rotatable on said sleeve" between the disc and catch a member,-"links pivotally connecting the col- ;lar with the clutch part whereby the collar and clutch part may be held into and out of frictional clutching engagement withthe opposite sideof said disc, 'andmeans for" holding said clutch part between the catch member and disc direction. w

6. In a safety hand crank for internal combustioncngines a hand crank member including a shaft portlon, acatch memberincluding a rigid sleeve rotatable on said keyed on the shaft at one side ofjsaid disc,

I ching engagement with the opposite sides of said disc.

against rotation in one" an enlargedrratchet wheel rotatable on the sleevefl between the disc and catch member f p providing transverse openings therethrough,

link bars, pivoted on said collar at the'jperatchet wheel ment at oppositesides of said disc when'the shaft is rotated. p 7. Ina safety crank for engines the combination with an internal combustion engine including a casing portion and a crank shaft, ahand crank including a shaft portion, means rotatably 7 mounting-the shaft portion in alignment with the crank shaft,

av catch member rotatably mounted on the shaft portion of the hand crank including a catch portion and a sleevebearing on said I: shaft portion of the hand crank for rotary and longitudinal sliding movement thereon,

said catch member being of nature for engagingthe crank shaft upontmovement" ofthe" hand crank longitudinally of the crank shaft, a disc keyed upon: said sleeve of'the catch member'in spaced relation with the catch portion of the catch membe ga clutch-part keyed upon the shaft of said wheelfriction disc pivotally and slidably mounted on the sleeve at the opposite side of said'tfirst mentioned disc from said clutch hand crank atone side of said'disc, a ratchet part, and links pivotally'connected to said ratchet wheel disc at one end of each and pivotally connected attheir'opposite ends to" the clutch part which is keyed on the shaft ofjsaid handcrank, said linksbe'ing of such :naturethat during normal position the disc which is keyedto thesleevc, the clutch part, and th'e' jratchet wheel disc are inspaced relation, and means cooperating with the ratchet wheel to normally prevent rotation thereof in one direction. a a i ROBERT G. ROBERTSON. 

